Area Forecast Discussion
Issued by NWS Lake Charles, LA
FXUS64 KLCH 302348
Area Forecast Discussion
National Weather Service Lake Charles LA
648 PM CDT MON MAY 30 2016
Contg to see hi clds movg in fm the w this eve. Cld decks
running around 040 to 060 w/ aftn dvlpmnt but this will fall
apart aftr ss. Looking for vfr wx to hold thru midnight.
.PREV DISCUSSION... /issued 321 PM CDT MON MAY 30 2016/
Earlier upper air analysis showed the mid/upper level ridge a
little weaker today with some height falls, as weak short wave,
noted on water vapor imagery from southern Oklahoma to lower
Texas, moves eastward. Latest integrated precipitable water values
from GPS-MET data, indicates better moisture also in play today
with values between 1.5 and 1.6 inches. With max daytime heating,
a few showers and thunderstorms are developing, mainly near sea
breeze and near Atchafalaya Basin convergence. This activity will
continue until early evening, with the loss of daytime heating.
Expect another fair and stable night, with the possibility of
some light patchy fog near sunrise.
Upper level ridging looks to be stronger again on Tuesday as short
wave exits the region. Therefore, hot and humid day, with very
limited chances for showers, and if any do develop, it will be
during the max heating time frame.
By mid week, northern stream trough will deepen some and help push
an upper level low to the east and begin to weaken upper level
ridge. As the northern stream trough departs on Thursday, it will
leave behind the upper level low over western Texas.
This cut off low, will meander slowly to the east across Texas
from the end of the week into the weekend. With no cap and low
convective temperatures, there will be high rain chances starting
late Thursday over southeast Texas, then over the entire forecast
area from Friday through the weekend.
This scenario usually means the possibility of heavy rainfall for
portions of the forecast area. Details this far out are hard to
pinpoint. However, progs do show deep Gulf moisture moving into
the region with Precipitable Water values between 1.75 and 2
inches, and Mean Relative Humidity values over 80 percent. Flow
aloft will become more divergent as upper level low nears to
provide lift to get activity going and enhance it. Progs also show
weak mid level winds and low bulk shear numbers from 0-6km, which
could mean slow storm movement, or training if any low level
mesoscale boundaries form. Just some of the ingredients needed for
the heavy rainfall.
Early next week, upper level ridge is expected to amplify over the
western U.S. with upper level trough developing over the eastern
U.S. This would place the forecast area in a drier northwest flow
aloft, that would help shear out upper low and push deeper
moisture to the east and south.
Weak surface ridge continues across the coastal waters this
afternoon with mainly light and variable winds. Onshore winds will
be a little bit stronger near shore and for the coastal lakes and
bays through early evening with a developing sea breeze.
For the remainder of the period, center of the surface ridge will
move slightly to the east and over the north central and northeast
Gulf of Mexico. This will allow for mainly light onshore winds,
and in turn, relatively low seas, to prevail.
.PRELIMINARY POINT TEMPS/POPS...
AEX 70 91 69 90 / 20 20 10 20
LCH 70 89 71 88 / 10 20 10 20
LFT 72 91 71 89 / 20 20 10 10
BPT 71 89 72 88 / 10 10 10 30